<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title></title>
    <style>

    </style>
</head>
<body>
    <h1>todolist</h1>
    <input type="text">
    <ul>

    <ul>
    <script>
        var oInput = document.getElementsByTagName("input")[0];

        oInput.onkeydown = function(event) {

            var event = event || window.event;
            if(event.keyCode == 13) {
                // 添加数据
                var data = this.value;
                addData(data);
                // 清空数据
                clearData();
            }
        }

        // 模糊查询
        oInput.oninput = function() {
            var arrLi = document.getElementsByTagName("li");
            var arr = [];
            
            for(var i = 0;i < arrLi.length;i++) {
                if(arrLi[i].firstChild.innerHTML.trim().indexOf(this.value.trim()) != -1) {
                    arr.push(i);
                }
            }
            // show
            show(arr);
        };


        function show(arr) {
            var arrLi = document.getElementsByTagName("li");
            // 隐藏所有
            for(var i = 0;i < arrLi.length;i++) {
                arrLi[i].style.display = "none";
            }

            // 显示
            if(arr.length > 0) {
                for(var i = 0;i < arr.length;i++) {
                    arrLi[arr[i]].style.display = "block";
                }
            } else {
                for(var i = 0;i < arrLi.length;i++) {
                    arrLi[i].style.display = "block";
                }
            }

        }

        function addData(data)  {
            var tempLi = document.createElement("li");
            var tempBtn = document.createElement("button");
            var tempSpan = document.createElement("span");
            var oUl = document.getElementsByTagName("ul")[0];

            tempBtn.innerHTML = "delete";
            tempBtn.name = "delete";
            tempSpan.innerHTML = data;
            tempLi.appendChild(tempSpan);
            tempLi.appendChild(tempBtn);
            oUl.appendChild(tempLi);
        }

        function clearData() {
            var oInput = document.getElementsByTagName("input")[0];

            // 不能用innerHTML
            oInput.value = "";
        }

        // 点击删除
        var oUl = document.getElementsByTagName("ul")[0];
        oUl.onclick = function(event) {
            var event = event || window.event;
            var target = event.target;

            if(target.name == "delete") {
                target.parentNode.parentNode.removeChild(target.parentNode);
            }
        };

    </script>
</body>
</html>
